Airbag and airbag module for a front passenger

ABSTRACT

An airbag module for a front includes an airbag made of a single, cut-out piece, which on either side of a symmetry axis ( 1 ) has an airbag section of identical shape and size. The airbag is arranged in the airbag module so that after the airbag has unfolded following a crash, the seam joining the curved edges ( 2   a   , 2   b ) of the airbag section ( 2, 3 ) extends away from the passenger along an at least substantially vertical plane, starting from a seamless area of the airbag and that the seamless area of the airbag, whose length is determined by the symmetry axis ( 1 ), faces toward the passenger. In addition, the airbag is folded only once along a symmetry axis ( 1 ). A further section ( 4, 5 ) is joined to each airbag section ( 2, 3 ) so as to form a space for receiving a diffuser.

BACKGROUND

A front-passenger airbag modules having airbags produced from a single,flat blank are known. PCT application WO 94/10008 describes an airbagconsisting of a blank having a rectangular section, which is adjoined,on opposite sides, by trapezoidal sections of identical size. Thesesections are adjoined to smaller, rectangular sections. The rectangularsections are intended for connecting the airbag to a tubular gasgenerator. During production of the airbag, part of the blank is foldedaround a central line, so that identical parts lie one on the other. Theoblique side edges of the trapezoidal section are then sewn together.After that, the upper and lower parts are pulled away from each otherperpendicularly with respect to the plane of deployment of the airbagblank. The edges of the opposite surface formed in the process, whichrun perpendicularly to the plane of deployment, are sewn together. Atubular gas generator is positioned between the airbag sections andfastened thereto so that its longitudinal axis runs parallel to theplane of deployment of the airbag blank.

The airbag is installed in the motor vehicle with its seams running inthe lateral region of the airbag, so that the head and chest regions ofthe occupant do not come into contact with the seams. This is desirable,since there is an increased risk of injury when the occupant impactsagainst the seam.

The same effect is obtained using an airbag module disclosed in Germanpatent publication DE 295 10 775 U1, which discloses an airbag producedfrom a single, flat blank having an airbag section of identical shapeand size on both sides of a line of symmetry. Furthermore, the airbaghas a blow-in opening that is arranged in the airbag module so thatafter the airbag has unfolded following a crash, the seam connecting theedges of the airbag sections runs away from the occupant along anapproximately vertical plane, starting from a seamless region of theairbag.

The known airbag modules have a disadvantage in that it is not possibleto sew up their single-piece airbags in one procedure, since theassignment of the airbag sections has to be changed between the sewingprocedures. The invention overcomes this disadvantage.

SUMMARY OF THE INVENTION

The present invention relates to an airbag module having a single-pieceairbag of a simpler design.

The airbag module according to the invention can be a front-passengerairbag module. The airbag thereof is made of a single, flat blank havingan airbag section of identical shape and size on both sides of a line ofsymmetry. The airbag is arranged in the airbag module so that, after theairbag has unfolded following a crash, the seam connecting the edges ofthe airbag sections runs away from the occupant along an at leastapproximately vertical plane, starting from a seamless region of theairbag, and the seamless region of the airbag, whose length isdetermined by the line of symmetry, faces the occupant. Furthermore, theairbag is only folded once along a line of symmetry. A further sectionadjoins each airbag section to form a holder for a diffuser.

This arrangement has the advantage in that the single-piece airbagblank, after having been folded around the line of symmetry, as a resultof which identically sized parts then lie one above the other, can besewn along its edges in one procedure to form an airbag, i.e., withoutthe airbag having to be folded into another position. A furtheradvantage, which has been determined in tests, is that thistwo-dimensional airbag, which is arranged in the airbag module in themanner according to the invention, unfolds following a crash in the samemanner as a substantially more complicated three-dimensional airbag.

It is also ensured in the case of this airbag module that the headregion and to the greatest possible extent also the chest region of theoccupant collide with the seamless region of the unfolded airbag.

A tubular gas generator is preferably provided as the gas generator inthe airbag module. A diffuser, which surrounds the tubular gasgenerator, is arranged so that its longitudinal axis runsperpendicularly with respect to the plane in which the airbag deploys.

In a preferred embodiment, the section for forming a holder for thediffuser is provided in that region of the airbag situated at the top inthe installed state. This embodiment is expedient for a “top-mounted”installation position of the airbag module. The airbag, when it unfolds,extends to a lesser extent in the direction of the windshield than inthe direction of the occupant.

In a further refinement, provision is made for the edges of the airbagto run in a curved manner.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained in more detail in an exemplaryembodiment with reference to drawings, in which:

FIG. 1 shows a single-piece airbag blank for a front-passenger airbagmodule;

FIG. 2 shows an airbag manufactured from the airbag blank of FIG. 1,after it has been turned over;

FIG. 3 shows the airbag according to FIG. 2 in section;

FIG. 4 shows a known three-dimensional airbag of a front-passengerairbag module in the unfolded position in the motor vehicle;

FIG. 5 shows the airbag taken along line V—V of FIG. 4 in a scaled-downillustration;

FIG. 6 shows the airbag, designed and arranged according to theinvention, of a front-passenger airbag module in the unfolded positionin the motor vehicle;

FIG. 7 shows the airbag according to FIG. 6 in section in a scaled-downillustration.

DETAILED DESCRIPTION

A single-piece airbag blank according to the present invention hasairbag sections 2, 3, and sections 4, 5, on both sides of a line ofsymmetry 1, for holding a diffuser 6, which extends around a tubular gasgenerator. Openings 7, 8 are provided to hold the diffuser 6 andopenings 9 to secure it. It can be seen from FIG. 1 that edges 2 a, 2 bare curved. The edge 2 a, which is situated at the top above the edge 2b after installing it in the airbag module, has a lesser curvature thanthe edge 2 b bordering the airbag at the bottom.

To produce the airbag, the airbag blank according to FIG. 1 is folded onthe line of symmetry 1 and the congruent regions are sewn together alongthe edges 2 a, 2 b. The finished airbag now has a blow-in aperture 10that remains open on one side for subsequently fitting the diffuser 6.In order to reinforce the blow-in aperture 10, fabric inserts 11 (FIG.3) can be added when sewing up the congruent regions along the edges 2a, 2 b. The inserts have identical holes to match the openings 7 to 9.During sewing, the fabric inserts are initially situated on the outsideand after the airbag has been turned over, are situated on the inside,as is illustrated in FIG. 3.

In order to fit the diffuser 6 in the blow-in aperture 10, the latter iswidened perpendicularly to the plane of projection and the diffuser ispushed in. The regions 12, 13 of the blow-in aperture 10 are then foldedover in the arrow direction and the openings 9 slipped over threadedplugs 14 of the diffuser. After that, the gas generator, which is notillustrated, can be pushed through the opening 7 into the diffuser andthe airbag can be fixed to the end sides of the diffuser via theopenings 7, 8 by means of known securing means.

FIG. 4 illustrates the unfolding characteristics of a known,three-dimensional airbag. In this case, two side parts 15, 16 areconnected to a circumferential central part 17 by seams 18, 19 (FIG. 5).In this airbag, the seams are situated to the sides of the central part,so that the region of the central part against which the occupantimpacts following a crash is seam-free. The airbag is arranged in a“top-mounted” installation position in a dashboard 20 and unfoldsbetween the latter and the windshield 21.

The same positive effect is also obtained with less complexity with theairbag cut and arranged according to the invention. In the case of thisairbag, the seams of the edges 2 a, 2 b run away from the occupant inthe center of the airbag, starting from the seamless region 22. In thecase of the present arrangement according to the invention, the occupantlikewise collides with the seamless region of the airbag although theseams run in the center of the airbag.

What is claimed is:
 1. An airbag module having an airbag and a diffuser,wherein: the airbag comprises a single, flat blank having a first airbagsection and a second airbag section on either sides of a line ofsymmetry, the first and second air bag sections having identical shapeand size, the first and second airbag sections being connected alongtheir edges to form first and second seams, and a seamless regionextending between the first and second seams, the airbag has a holderthat holds the diffuser, the airbag is arranged in the airbag module sothat the airbag unfolds following a crash, with the first and secondseams extending away from an occupant substantially along a verticalplane of the line of symmetry, starting from the seamless region of theairbag, with the seamless region of the airbag, whose height isdetermined by the line of symmetry, facing the occupant, and the firstand second seams run along centrally of the airbag.
 2. An airbag moduleaccording to claim 1, wherein the diffuser is adapted to surround atubular gas generator and is arranged so that its longitudinal axis runsperpendicularly with respect to a plane in which the airbag deploys. 3.An airbag module according to claim 1 or 2, wherein the diffuser holdercomprises first and second adjoining sections adjoining respectivelyfrom the first and second seams, the diffuser holder having an openingfor receiving a gas generator, the diffuser holder being adapted for atop installation in a vehicle below a windshield.
 4. An airbag moduleaccording to claim 1, wherein the first and second seams of the airbagare curved.
 5. An airbag module according to claim 4, wherein the firstseam is situated above the second seam upon the airbag unfolding, thefirst seam having a lesser curvature than the second seam, which ispositioned bordering at a bottom of the airbag.
 6. An airbag moduleaccording to claim 1, wherein the airbag has a single fold along theline of symmetry.
 7. An airbag for a vehicle, comprising: a first airbagsection and a second airbag section shaped and sized as the first airbagsection, the first and second airbag sections extending on left andright sides from a line of symmetry, wherein the first and second airbagsections are integrally formed at the line of symmetry, wherein thefirst and second airbag sections are connected along their edges to formfirst and second seams, and a seamless region extending along the lineof symmetry between the first and second seams, wherein the airbag isadapted to unfold with the first and second seams extending away from anoccupant substantially along a vertical plane of the line of symmetry,starting from the seamless region of the airbag, and wherein the firstand second seams run substantially along the vertical plane of the lineof symmetry when the airbag unfolds, with the seamless region, whoseheight is determined by the line of symmetry facing the occupant.
 8. Anairbag according to claim 7, wherein the first and second sections havea single fold along the line of symmetry.
 9. An airbag according toclaim 7, wherein the first and second seams of the airbag are curved.10. An airbag according to claim 9, wherein the first seam is situatedabove the second seam when the airbag unfolds, the first seam having alesser curvature than the second seam, which is positioned bordering ata bottom of the airbag.